色多多在线观看播放-色多多在线观看高清免费-色多多在线观看视频-色多多在线看-欧美aaaaa性bbbbb小妇-欧美aaaav免费大片

Innovation distinguishes between a leader and a follower.

I love to think of nature as an unlimited broadcasting station, through which God speaks to us every hour, if we will only tune in.

Collaboration in mathematics is essential; no one can solve all the problems alone.

In Russia, severity of laws is compensated for by their non-enforcement.

人生苦短，必須快樂(lè)。